A New Type of Waveguide Directional Coupler

A type of waveguide directional coupler is described which has been carefully measured over a 12 per cent wavelength band centered at 3.3 centimeters. It combines the advantages of high directivity, low input standing-wave ratio, ease of design, and universality of application. Sufficient theory is given to explain the principles of its operation, and to allow its performance to be duplicated at other wavelengths. A number of design and performance curves are included.